1. roc4fun's Avatar
    Hi All, I have a L520 that was purchased as an AT&T GoPhone. It has never been used with AT&T, I've always used it with Straight Talk, works flawlessly. It has AT&T branding and reports AT&T as being the carrier.

    AT&T is slow rolling out the Denim update, so I thought I would unlock it and get updates directly from Microsoft. I used the AT&T unlock service and was given an unlock code. The instructions call for inserting the non-AT&T sim and the phone prompting you for the unlock code. I've always used a non-AT&T sim and never gotten the unlock prompt.

    How can I use my unlock code?

    Will this type of unlock allow me to get updates directly from Microsoft?

    Is there any downside to doing this?

    Thanks in advance,

    04-29-2015 07:03 AM
  2. RumoredNow's Avatar
    Right. Any ATT mvno SIM like Straight Talk, Cricket, Net 10, etc. does not trigger the unlock screen. The SIM just works.

    Open Phone App and on the dialer pad* enter ##7820# you don't even have to press call it will take you to the "Lock Status" page as soon as the last # goes in. You will see a padlock (locked) in front of a SIM for an icon and a box beneath that. Tap the box to bring up the numberpad. Input the code ATT gave you and press enter. You will see it process and then the padlock will unlock. Your unlock is done. A hard reset or flashing with a reset tool will not undo the unlock.

    Unfortunately, this does not free your phone from needing ATT to push an OTA. A phone will always update after its hardware designated Region/Country/Model/Carrier no matter where in the world you take it, what SIM is in it or no SIM and whether it is carrier locked or not.

    There is no downside to doing the unlock. It can only enhance the phone. Now you are free to use other services such as T-Mo or a T-Mo mvno and can travel internationally and use local SIM cards when doing so. An unlock actually increases a phone's value for these reasons.

    *Pro Tip: Save hash codes like ##7820# in your contacts and store them in the cloud so they come to every phone you ever have and you don't loose the code, forget it or have to search around for it again. I label this one "Carrier Lock Status" in my contact list.
    xandros9 likes this.
    04-29-2015 08:56 AM
  3. roc4fun's Avatar
    Thanks RumoredNow,

    Just the information I was looking for.

    The tip about the hash codes is especially good. Are there lists of these?
    04-29-2015 10:37 AM
  4. RumoredNow's Avatar
    They are around... I don't have a link to any lists that are current for Lumia, just general GSM hash codes that are rather old school. Like this one: GSM Feature Codes

    Others I have stored in my contacts are:
    ##3282# "Field Test Menu" which may not be accessible on every Lumia due to some Firmware lockouts.
    ##634# "Lifetime Counter" which shows the total in call time since the phone was built (plus some other minor details).
    ##4678255# "Tier3 Status" shows silent installer activity and will show if any Apps fail to update. The downside is that the titles are in Hexidecimal.
    *#06# "Show IMEI" 'nuff said.
    xandros9 likes this.
    04-29-2015 12:07 PM

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